Also as an interviewer, you notice things beyond just the dance. I and other interviewers I know have not passed people with mostly-correct answers due to thing

Also as an interviewer, you notice things beyond just the dance. I and other interviewers I know have not passed people with mostly-correct answers due to things like being rude/condescending or other poor communication skills. One thing the “dance” does is show what someone is like in a difficult problem solving situation and how they respond to it. Is the stress a confounding variable? Yes, for sure. It’s an imperfect solution to a hard problem